OPM_GET_INFO_PARAMETERS structure (ksopmapi.h)
Contains parameters for the IOPMVideoOutput::GetInformation method.
Syntax
typedef struct _OPM_GET_INFO_PARAMETERS {
OPM_OMAC omac;
OPM_RANDOM_NUMBER rnRandomNumber;
GUID guidInformation;
ULONG ulSequenceNumber;
ULONG cbParametersSize;
BYTE abParameters[OPM_GET_INFORMATION_PARAMETERS_SIZE];
} OPM_GET_INFO_PARAMETERS;
Members
omac
An OPM_OMAC structure that contains a message authentication code (MAC) for the data in the rest of the structure.
rnRandomNumber
An OPM_RANDOM_NUMBER structure that contains a cryptographically secure 128-bit random number.
guidInformation
A GUID that defines the status request. For more information, see OPM Status Requests.
ulSequenceNumber
The status sequence number. The application must keep a running count of status requests. For each request, increment the sequence number by 1.
On the first call to GetInformation, set ulSequenceNumber equal to the starting status sequence number, which is specified when the application calls IOPMVideoOutput::FinishInitialization. On each subsequent call, increment ulSequenceNumber by 1.
Exception: If the status request fails, do not increment the sequence number. Instead, re-use the same number for the next status request.
cbParametersSize
The number of bytes of valid data in the abParameters member.
abParameters[OPM_GET_INFORMATION_PARAMETERS_SIZE]
The data for the status request. The meaning of the data depends on the request. For more information, see OPM Status Requests.
Remarks
Initialize this structure as follows:
- Generate a cryptographically secure 128-bit random number and copy it to the rnRandomNumber member. Do not re-use this number after calling GetInformation.
- Fill in the remaining structure members, except for the omac member.
- Use the OMAC 1 algorithm to calculate a message authentication code (MAC) for the block of data that appears after the omac member (excluding the omac member).
- Copy the MAC to the omac member.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps only] |
| Minimum supported server | Windows Server 2008 [desktop apps only] |
| Header | ksopmapi.h (include Opmapi.h) |